(1) Field of the Invention
An endoscope having a viewing window for observation of the body cavity illuminated by light from an illumination window and wherein forceps for collecting vital tissue or a tube for introducing a contrast medium therethrough for photographing of the body organ are guided into the visual field of the viewing window.
(2) Description of Prior Art
It is known to provide raising means in an endoscope for raising and guiding the forward end of an implement, such as forceps for collecting a piece of vital tissue or a tube for introducing contrast medium therethrough for X-ray photography. The known raising means is provided with its working surface being inclined with respect to the vertical plane which includes the optical central axis of the viewing window to thereby guide the forward end of the implement into the visual field. However, the known raising means has various drawbacks due to the limited, narrow inner diameter of a channel through which the implement is introduced. The present invention is an improvement of such known raising means in the endoscope.
Thus, the present invention relates to raising means in endoscopes for implement such as forceps introduced to collect vital tissue of body cavity, for example, stomach or duodenum, or tubes introduced to observe or photograph pancreatic duct (ductus pancreaticus) or bile duct (tubulus biliferus), and more particularly to an improvement in raising means for, e.g., forceps introduced to collect vital tissue or tubes introduced to observe or photograph pancreatic duct or bile duct, such that, in diagnosis utilizing an endoscope inserted into a body cavity in question, said forceps or tube may be projected through an opening formed in a metal fitting at the front end of a flexible portion of the endoscope, the opening being situated in side-by-side relationship with a viewing window so that said forceps or tube thus projected may be appropriately guided into a visual field of said viewing window.
The endoscope generally includes, in its flexible tube to be inserted into the body cavity, two separate optical fibre bundles each comprising a bundle of fibre glass. One of these bundles is the optical fibre bundle for illumination adapted to emit light from the illuminating window formed adjacent the front end of the flexible tube to be inserted into the body cavity onto the inner wall of this body cavity to be inspected and this optical fibre bundle is connected at its opposite end, i.e., the end outside the body cavity with the light source for illumination. The other bundle is the optical fibre bundle for observation permitting the inner wall of the body cavity illuminated by the light emitted from said illuminating window to be viewed through said viewing window formed in the flexible tube adjacent its front end and through the manipulator unit adapted to be manipulated by the physician externally of the body cavity or to be photographed by the camera mounted in said manipulator unit. Briefly, one of these two optical fibre bundles is used to illuminate the interior of the body cavity and the other is used to observe the interior of the body cavity thus illuminated. Differing from such endoscopes which are exclusively used to observe or diagnose an inner wall of the body, particulary the diseased spot therein, there has recently been developed a multipurpose endoscope with the flexible tube to be inserted into the body cavity including the additional channel through which implements, such as forceps, can be introduced and externally manipulated to collect a part of the vital tissue for inspection, or through which a tube can be introduced to observe or photograph pancreatic duct or bile duct. The implement such as the forceps or the tube is introduced from the manipulator unit connected to the flexible tube at its end outside the body cavity through said channel extending through the flexible tube in parallel to said two optical fibre bundles into the body cavity in which said implement is projected outwardly from the flexible tube through its front end at a position adjacent the illuminating window and the viewing window towards the inner wall of the body cavity. The projected portion of the implement is selectively directed by external manipulation to the diseased spot to be inspected or to the pancreatic duct or the bile duct within the visual field of said viewing window. Obviously, said illuminating window and said viewing window are not formed in the end surface which extends in a plane orthogonal to the length of the flexible tube but in the peripheral outer wall of a substantially cylindrical metal fitting situated at the front end of said flexible tube for convenience of manipulation or diagnosis. It is obvious that the illuminating window is formed closely adjacent the viewing window, and said implement is projected orthogonally or transversely of the length of the flexible tube through the opening formed in the front end metal fitting adjacent the viewing window. To achieve this, the implement introduced along the channel axially extending through the flexible tube must abruptly change its direction at the position corresponding to said metal fitting around the front end of the flexible tube somewhat transversely of the direction in which the implement has been introduced. For such abrupt change of direction, said metal fitting is provided with a raising device or raising means adapted to raise the front end of the implement so that the direction in which said implement is projected may be freely controlled. The present invention relates to such raising means with which the metal fitting around the front end of the flexible tube is provided for controllably changing the direction in which the implement introduced into said flexible tube is projected. As will be apparent from the foregoing description, the illuminating window formed in the cylindrical outer wall of the metal fitting around the front end of the flexible tube should be able to adequately illuminate the visual field of the viewing window while the implement should be projected through the opening formed closely adjacent the viewing window so that the end of said implement thus projected out from said opening may be controllably oriented utilizing the visual field of the viewing window.
On the other hand, it is also required to arrange the raising means in close vicinity to said opening through which the end of the introduced implement is projected, and such that the raising means is adapted to be externally controlled from the manipulator unit connected to the outer end of the flexible tube by a wire connected to said manipulator unit, the wire extending through the flexible tube to the front end thereof, and associated with said raising means. Thus, various members must be crowded in the interior of the front end metal fitting and since the fitting has a relatively small diameter, the fitting necessarily has an extremely complicated inner construction. Specifically, this metal fitting must be provided with at least the illuminating window and the associated members, the viewing window and the associated members, a curved passage to guide the introduced implement and the raising means for this introduced implement. Additionally, the metal fitting must be incorporated therein with the air supply tube, the water supply and liquid suction tube to wash away mucus in the body cavity and the openings associated with these tubes. In consequence, it is difficult to provide sufficient space for these individual members. Particularly, for example, the front end metal fitting and the flexible tube following this metal fitting may be inserted through the oral cavity into the body cavity and therefore their outer diameters are necessarily governed by the minimum inner diameter of various organs in the body cavity. If the outer diameters of the front end metal fitting and the flexible tube are increased in order to facilitate incorporation of the respective members, there would be caused unbearable pain to the patient as said metal fitting and said flexible tube are advanced into the body cavity. On the other hand, if the outer diameters of said metal fitting and said flexible tube directly connected therewith are reduced in order to ease pain to the patient as effectively as possible and to facilitate insertion thereof into the body cavity, a technical difficulty in mounting the respective members within the front end metal fitting and the flexible tube would occur. The problem would be very serious particularly if the outer diameter of said optical fibre bundle for illumination is reduced, because the light quantity which is available to illuminate the diseased spot would be thereby limited. This would be similar in the case where the diameter of the optical fibre bundle for observation is reduced. Thus, if the outer diameter of said optical fibre bundle for observation is reduced, the visual field for observation would be so constricted or darkened that the desired operation of observation or photographing might be disadvantageously obstructed. As a result, it is impossible to reduce the outer diameters of these optical fibre bundles to the desired values.